player: allow playing directories

If a directory is encountered, replace it with its contents in the
internal playlist.

This is messed into demux_playlist.c, because why not. STREAMTYPE_DIR
could be avoided by unconditonally trying opendir() in demux_playlist.c,
but it seems nicer not to do weird things like calling it on real files.

This does not work on Windows, because msvcrt is retarded.

demux/demux_playlist.c

@@ -15,7 +15,10 @@
  * with mpv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdlib.h>
+#include <string.h>
 #include <strings.h>
+#include <dirent.h>
 
 #include "common/common.h"
 #include "options/options.h"
@@ -23,6 +26,7 @@
 #include "common/playlist.h"
 #include "options/path.h"
 #include "stream/stream.h"
+#include "osdep/io.h"
 #include "demux.h"
 
 #define PROBE_SIZE (8 * 1024)
@@ -47,6 +51,7 @@ struct pl_parser {
     bool error;
     bool probing;
     bool force;
+    bool add_base;
     enum demux_check check_level;
     struct stream *real_stream;
 };
@@ -204,6 +209,51 @@ static int parse_txt(struct pl_parser *p)
     return 0;
 }
 
+static int cmp_filename(const void *a, const void *b)
+{
+    return strcmp(*(char **)a, *(char **)b);
+}
+
+static int parse_dir(struct pl_parser *p)
+{
+    if (p->real_stream->type != STREAMTYPE_DIR)
+        return -1;
+    if (p->probing)
+        return 0;
+
+    char *path = mp_file_get_path(p, bstr0(p->real_stream->url));
+    if (strlen(path) >= 8192)
+        return -1; // things like mount bind loops
+
+    DIR *dp = opendir(path);
+    if (!dp) {
+        MP_ERR(p, "Could not read directory.\n");
+        return -1;
+    }
+
+    char **files = NULL;
+    int num_files = 0;
+
+    struct dirent *ep;
+    while ((ep = readdir(dp))) {
+        if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
+            continue;
+        MP_TARRAY_APPEND(p, files, num_files, talloc_strdup(p, ep->d_name));
+    }
+
+    if (files)
+        qsort(files, num_files, sizeof(files[0]), cmp_filename);
+
+    for (int n = 0; n < num_files; n++)
+        playlist_add_file(p->pl, mp_path_join(p, bstr0(path), bstr0(files[n])));
+
+    closedir(dp);
+
+    p->add_base = false;
+
+    return num_files > 0 ? 0 : -1;
+}
+
 #define MIME_TYPES(...) \
     .mime_types = (const char*const[]){__VA_ARGS__, NULL}
 
@@ -214,6 +264,7 @@ struct pl_format {
 };
 
 static const struct pl_format formats[] = {
+    {"directory", parse_dir},
     {"m3u", parse_m3u,
      MIME_TYPES("audio/mpegurl", "audio/x-mpegurl", "application/x-mpegurl")},
     {"ini", parse_ref_init},
@@ -248,6 +299,7 @@ static int open_file(struct demuxer *demuxer, enum demux_check check)
     p->log = demuxer->log;
     p->pl = talloc_zero(p, struct playlist);
     p->real_stream = demuxer->stream;
+    p->add_base = true;
 
     bstr probe_buf = stream_peek(demuxer->stream, PROBE_SIZE);
     p->s = open_memory_stream(probe_buf.start, probe_buf.len);
@@ -269,7 +321,7 @@ static int open_file(struct demuxer *demuxer, enum demux_check check)
     p->s = demuxer->stream;
     p->utf16 = stream_skip_bom(p->s);
     bool ok = fmt->parse(p) >= 0 && !p->error;
-    if (ok)
+    if (p->add_base)
         playlist_add_base_path(p->pl, mp_dirname(demuxer->filename));
     demuxer->playlist = talloc_steal(demuxer, p->pl);
     demuxer->filetype = fmt->name;

stream/stream.h

@@ -31,6 +31,7 @@
 enum streamtype {
     STREAMTYPE_GENERIC = 0,
     STREAMTYPE_FILE,
+    STREAMTYPE_DIR,
     STREAMTYPE_DVB,
     STREAMTYPE_DVD,
     STREAMTYPE_BLURAY,

stream/stream_file.c

@@ -238,6 +238,7 @@ static int open_f(stream_t *stream)
         .fd = -1
     };
     stream->priv = priv;
+    stream->type = STREAMTYPE_FILE;
 
     bool write = stream->mode == STREAM_WRITE;
     int m = O_CLOEXEC | (write ? O_RDWR | O_CREAT | O_TRUNC : O_RDONLY);
@@ -278,9 +279,9 @@ static int open_f(stream_t *stream)
         struct stat st;
         if (fstat(fd, &st) == 0) {
             if (S_ISDIR(st.st_mode)) {
-                MP_ERR(stream, "File is a directory: '%s'\n", filename);
+                stream->type = STREAMTYPE_DIR;
-                close(fd);
+                stream->allow_caching = false;
-                return STREAM_ERROR;
+                MP_INFO(stream, "This is a directory - adding to playlist.\n");
             }
 #ifndef __MINGW32__
             if (S_ISREG(st.st_mode)) {
@@ -302,7 +303,6 @@ static int open_f(stream_t *stream)
         stream->seekable = true;
     }
 
-    stream->type = STREAMTYPE_FILE;
     stream->fast_skip = true;
     stream->fill_buffer = fill_buffer;
     stream->write_buffer = write_buffer;